perpendicular slope & equation of perpendicular lines
DESCRIPTION
Perpendicular Slope & Equation of Perpendicular Lines. Lesson 5-8. Math Vocabulary. Perpendicular Lines: two lines on a graph, that DO intersect, forming a right angle, based on opposite slope. Finding Parallel Slope…. Perpendicular Lines have… The opposite/reciprocal slope! - PowerPoint PPT PresentationTRANSCRIPT
LESSON 5-8
Perpendicular Slope & Equation of Perpendicular
Lines
Math Vocabulary
Perpendicular Lines:two lines on a graph, that DO intersect,
forming a right angle, based on opposite slope
Finding Parallel Slope…
Perpendicular Lines have…The opposite/reciprocal
slope!
If y = 3/5 x – 4
m = 3/5
then perpendicular slope perpendicular m = - 5/3
Finding Parallel Slope…
Find the slope of a line perpendicular to the equation…
y = -5 x – 3
m = -5
perpendicular m = 1/5
Find the slope of a line perpendicular to the equation…
x – 3y = 7
*Needs to be in y = mx + b
x – 3y = 7 -x -x -3y = -x + 7 -3 -3 -3
y = 1/3 x – 7/3
m = 1/3
perpendicular m = - 3
Finding Perpendicular Slope…
Find the slope of a line perpendicular to the equation…
y = -4x + 7
m = -4
perpendicular m = ¼
Find the slope of a line perpendicular to the equation…
3y + 6x = 12
*Needs to be in y = mx + b
m = -2
perpendicular m = ½
Equation of a line with Perpendicular Slope…
Finding the equation of a line perpendicular to y = -4x + 1
AND… that passes thru the point (-8, 0)
1) Name the current slope m = -4
2) Name the perpendicular slopeperpendicular m = 1/4
2) Solve to write the equation with…
m = 1/4, thru (-8, 0)
y = mx + b0 = ¼ (-8) + b0 = -8/4 + b0 = -2 + b+2 +2 2 = b
Eq. y = ¼ x + 2
Practice…
Find the parallel & perpendicular slope of each equation of a line…
a) y = - 8/3x + 5 parallel m =perp m =
b) 15x + 3y = -3 parallel m =perp m =
c) Write the equation of a line perpendicular to y = -2x + 1, and that passes thru (-4, 3)
Homework
p. 253-254 #13-17, 21-23, 42, 43